Joint Parameters Estimation for CDMA Signals

In wireless communications,mobiles emit signals that arrive at a receiver with multiple paths,each with its own direction of arrival(DOA),path delay,fading,and Doppler shift frequency,which influence the quality of communication seriously.These parameters should be taken into account in array signal processing.Based on CDMA signal,a novel Space-Time approach is proposed to estimation the DOA,time delay,and the Doppler shift frequency.Because utilize special signal model about space-time-frequency of mobile communications.The proposed algorithm has simpler structure and high quality of division.The simulation results show the feasibility and effectiveness of the method.     

Improved Signal Detecting Algorithm for Burst Communication

Signal detecting is the first task for Burst communication. The paper proposes an improved double sliding window algorithm to detect burst signal based on the feature of preamble sequence. Additionally, theory analysis and computer simulation of the improved algorithm are also made in several typical channels. At last, the algorithm is realized with FPGA, and the result indicates that the improved algorithm can detect burst signal only within the time of 6 symbols, obviously improving the capability of signal detecting algorithm.     

Application of Bispectrum Estimation to Analyzing Pulse Signals

According to non-Gaussianity and randomness of the Pulse Signals, the bispectrum estimation is used to analyze the signals for the purpose of extracting the unusual information of the signals of-the drug abusers and educing the judgment of how to distinguish drug abusers from healthy persons. The phase of bispectrum carries the important feature information in signal processing. The feature vector of the average phase information based on the indirect nonparametric bispectrum estimation is extracted and used to analyze the Pulse Signals of 15 heroin addicts and 15 healthy persons. It is found that the average phase Ph of heroin addicts on a specified frequency region is generally lower than that of healthy persons. Using the average phase Ph as characteristic parameter, a critical parameter is determined that is used to classify heroin addicts and healthy persons. Thus, all of the 15 healthy addicts are identified. Only one heroin person is misjudged. Experiment results of classification show that the method is feasible and effective.     

数量性状分离分析中分布参数估计的IECM算法

在主基因＋多基因混合遗传分析中, 随着模型的扩展, 估计成分分布参数的EM算法 显 示其局限性。 本文在ECM算法和剖分成分分布方差为主基因、 多基因及环境三种方差组分 基 础上, 推演出S个CM步骤的一般迭代公式, 称为迭代ECM算法(简称IECM算法)。 文中 给出利用 个别分离世代鉴定主基因和多基因存在, 以及利用联合多个     

A Data Detector Based on Channel Equalizer Designed for the Downlink of CDMA Systems

In code-division multiple-access (CDMA) systems,sub-optimum multi-user or joint detection algorithms have been studied recently, which are mostly designed for the uplink situation. The algorithms are too complex to implement for the downlink situation. The conventional receiver consisting of matched filters is often inefficient in eliminating MAI. The authors propose a data detection algorithm designed for downlink of CDMA systems which introduce channel equalization to eliminate MAI. It consists of a channel equalizer and code matched filter. The equalization algorithm is based on zero forcing (ZF) criterion.The performance of the algorithm is better than metched filter's and its complexity is cower than tunt of sub-optimum multi-user detection.